We propose to conduct research and development towards a ceramic scintillator composed of LSO:Ce. It is well known that crystalline LSO is one of the highest performance scintillators in term of light output and timing. Only impediment stands in the way of LSO assuming a commanding position in most areas of medical applications: its unacceptably high cost, which is due largely to the very high temperatures necessary to grow the crystals and the consequently very low yield of good crystals (high light output and no afterglow). Ceramic processing, however, offers a low-cost alternative, as demonstrated by our success with transparent ceramic scintillators of Lu2O3- Ceramic fabrication takes place at a much lower temperature, which should substantially reduce the concentration of defects that give rise to afterglow. Preliminary work indicates that ceramic LSO can indeed be prepared with light output nearly the same as from good crystals. While its non- cubic structure prevents full transparency, LSO should readily reach the translucency levels of Gd2O2S:Pr, currently used in CT. This would provide a scintillator vastly superior to Gd2O2S and CdWO4 in CT and fully applicable to PET and other uses, at costs significantly lower than for single crystals. PROPOSED COMMERCIAL APPLICATIONS: Because currently available scintillator materials cannot provide the necessary performance, medical radiography has been unable to tap the full potential of digital techniques for data acquisition and processing. The development of a material that can fill this need will revolutionize radiological techniques and greatly enhance their diagnostic power. The immediate market includes both static and tomographic imaging, X-ray and nuclear sources, and potentially extends to virtually every X-ray machine now in use.